"It can be annoying and intrusive," he said. "You get call sheets, there's no names, everybody's got a number! You're number 11. You're 33. You're looking at the call sheets wondering who's working today, and it's like, 'Oh, I loved 22's work. She's twice as good as 11.'"
Hamill, 64, said his advancing age has also made it more difficult to remember his lines as castmembers are banned from taking scripts home, reported Contactmusic.
"I'm in the elderly recluse stage of my career, I have to write cartoons in the margins to make me remember these lines. Need a script you can write on and take home and look and read! So they let me have one scene, and I keep it on my person."
Hamill's fellow franchise veteran Carrie Fisher and "The Force Awaken" stars Daisy Ridley and Oscar Isaac will also return for the highly-anticipated Episode VIII, which will arrive in US theatres in 2017.